Apparatus for liquid-liquid contacting



S. C. CARNEY APPARATUS FOR LIQUID-LIQUID CONTACTING March 16, 1954 2Sheets-Sheet l Filed NOV. 18, 1948 ATTORNEYS March 16, 1954 s. c.CARNE-Y 2,672,406

APPARATUS FOR LIQUID-LIQUID CONTACTING Filed Nov. 18, 1948 2Sheets-Sheet 2 JNVENToR.

. scc/Amm Wma-K4 Patented Mar. 16, 1954 APPARATUS FOR LIQUID-LIQUID CONTACTIN G Samuel C. Carney, Bartle Phillips Petroleum Co Delaware sville,Okla., assigner to mpany, a corporation of Application November 18,1948, Serial No. 60,778

Claims.

This invention relates to a method of and apparatus for liquid-liquidcontacting. In another aspect, it relates to a contacting unit for usein such apparatus.

There are numerous industrial operations in which two liquid phases arebrought into intimate contact for the purpose of purication, separationor reaction. .In one type of operation, known as liquid-liquidextraction, two liquid phases are brought into contact for the purposeof separating or extracting one or more of the components of one of theliquids by contact with 'a second liquid generally known as the solvent.Such liquid-liquid extraction processes are frequently used forseparating various hydrocarbon mixtures, such as close boiling paraflinsand naphthenes, which cannot be separated by fractionation. Two liquidphases are also brought into intimate contact in various treatingoperations in which some impurity, such as hydrogen sulde, mercaptans ora small amount of an aluminum halide catalyst,v is removed fromrahydrocarbon mixture. A similar type of operation is also used in variouscatalytic hydrocarbon conversion processes, such as alkylation, in whichthe liquid phase hydrocarbon reactants are brought into intimate contactwith a liquid phase catalyst so as to produce a reaction. Y *Y lnaccordance with the present invention, a very intimate contact isobtainedbetween the liquids by dispersing droplets of liquid to becontacted into a continuous phase of a second liquid. The second liquidis preferably directed perpendicularly against the liquid droplets toproduce a shearing action. The present invention contemplates thecombination of this dispersion and shearing action with countercurrentmovement oi the heavy and lightliquids, this shearing and dispersingaction occurring continuously throughout a large region and at very highvelocities. y,

The countercurrent action is made possible by centrifuging the liquidsto be treated in several zones, thereby causingthe heavier liquid totravel toward the periphery of each zone while the light liquid movestoward the center of the zone. As a result of this separation, theoverall iiow through the apparatus may take place in a countercurrentmanner. I provide apparatus for supplying droplets of `light liquid tothe peripheral region of each treatingzone for supplying droplets ofheavy liquid tothe inner'region of each zone. lThe droplets aredispersedinto the centrifuge zones and sheared'by the centrifugedliquidsfin thesezones.Y The method and appaviews taken along the lines 22, 3 3,

ratus of this invention are well adapted to the use of severalcontacting stages, and enables several equilibrium extraction stages tobe provided within a relatively short contacting zone.

It is an object of the invention to provide a method of and apparatusfor effecting intimate contact between two immiscible liquids.

It is a further object of the invention to provide apparatus foreffecting countercurrent movement of the liquids to be contacted withefficient contacting of the liquids as they move countercurrentlythrough the mixing vessel.

It is a still further object of the invention to provide apparatus whichis rugged and durable in construction, reliable in operation, of greatsimplicity, and which can be built at low cost.

Various other objects, advantages and features of the invention willbecome apparent from the following detailed description taken inconjunction with the accompanying drawings, in which:

Figure 1 is a vertical sectional view partly in elevation of my novelliquid-liquid contacting apparatus; and

Figures 2, 3 and 4 are, respectively, sectional and 4 4 of Figure 1,looking in the direction of the arrows.

Referring now to the drawings in detail, and particularly to Figure 1,the apparatus comprises a generally cylindrical casing le having a lowerfrusto-conical end plate Il partially defining a reservoir l2 for heavyliquid and an upper frustoconical end plate I3 partially defining areservoir lli for light liquid. In the present preferred embodiment ofthe apparatus, the axis of the casing is positioned vertically and lightliquid is admitted to the contacting vessel through an inlet i5 fromwhich is passes upwardly through the contacting apparatus to thereservoir ifi and an outlet i6 at the top of the vessel, the backpressure at outlet I6 being controlled by a valve I1. Liquid ofrelatively high specific gravity is admitted through an inlet i8 fromwhich it passes downwardly through the contacting apparatus incountercurrent flow with respect to the light liquid and finally reachesthe reservoir l2 from which it is discharged through an outlet i9, theback pressure at outlet I9 being controlled by a valve ma. A perforatedscreen 20 is provided adjacent reservoir I2 and a perforated screen 2|is provided adjacent reservoir It, these screens tending to preventmixing of the light and heavy,

liquids at the top and vessel.

` A vertically extending shaft 22'is journall'ed bottom portions of theperforated sleeves 21a to 21d, inclusive, which rotate with the shaft.Each impeller includes a Y plurality of vanes 23, Figure 2, and thesevanes are of the proper geometrical'c'ontour to provideA a largedifference in static pressurev between the center and the periphery ofth vessel, and a maximum separation between the 'heavy` andlight liquidswith a minimum power requirement. It will be understood that theimpellers provide' a continuous phase of heavy liquid at the peripheryoffthenvessel, and a continuous` phase of light liquid-at the innerregion of the vessel, with a vertical.. cylindrical interface-betweenthe phases. The; impellers 2liv arel spaced at equal distances' alongtheshaft, and liquid conveying unitsl 29a, 29h, Bilatb are mountedbetween the respective impellers, theseunits cooperating with the casingI0 to form.. a separate chamber 3Ia to 3Ie foreachoftheimpellers. ItWill be noted that theaunits 29are disposed alternately with theunitssothat each impeller chamber has a unit 29 at one end-thereof and aunit 30 at its other end. It will also be notedthat the impell'er blades..28 completely iill chambers tlbv to Sie', inclusive,V except for'.cutaway portions 22m which are provided to accommodate Pitot tube unitsto behereafter described.

Each ofwthesleeveshas a solid end piece 33- byfwhich. itis attached tothe shaft and a num- -berfotperforations 3.4' are formed in thekcylindrficalportion of the sleeve; The unit 29a is formed: from a pairofspaced annular plates 3c which are xed to the casing l0 and. each ofthesefstationary'plates hasan: inner flanged portion .which cooperateswith a-.flange'on4 the ad" jacentrotatingfsleeve-21a01:27h to form alabyrinth joint 3i. isia. series of arcuate generally radial tubes 38,Figures 1- and'- 4,.each of which has an inlet portion39-.extendingthroughthe upper plate 36 and protr-udingr into. thee upperadjacent impeller chamberv 3Ia, `the tipof the-tube being oriented sothat. when therimpeller rotates, liquid from the outerrregionfof theimpeller chamberis forced intothe tube inlets. Althoughtheinletportions, as

shown, all lie in a common-.horizontal plane; they may` in some cases bearrangedin a helical formation-to prevent interference between adjacentinlets. The outlet portion 40'of each tube 38 ispositioned solas todisehargeliquid into a central, outlet chamber` 42 which communicateswiththe perforated sleeves 21a and 2lb. Accordingly, the'tubes 38 areadapted to convey'heavy liquidfromthe .outer region of impeller. chamber31a! to-theinner annular chamber 42 from which a portionof the heavyliquid is recycled through sleeve Z'Iawhile the remainder ofthe `heavy4liquid passesthrough sleeve 2lb into the lower adjacent .impellerchamber 3Ib. The annular chamber 42, .of course, may vary in size inaccordance with the amount of-.liquidhandled by the tubes 381 The tubes.38 lresemble a lshrouded, pump im-l peller in construction while theirVoperation is- Very similar to that of a group of Pitot tubes.A

Ihat,.isthe. tubes convertgthe .velocityi potential Mounted between theplatesV 3B' energy, and pressure of the liquid entering their inletsinto head capable of discharging such liquid through the tube outlets.

Unit 28a further includes a series of vertical nipples or pipes 43 whichare disposed circumferentially of the shaft. These nipples are adaptedto permit passage of the lighter liquid from the inner region ofimpeller chamber 3Ib to the inner region of impeller `chamber 3 Ia. Theconstruction of unit 29h is similar to that of unit 29a, and.accordingly, unit 29h is adapted to permit passage of heavy liquid fromthe outer region of chamber 3Ic to the inner region of chambers 3io and3Icl, and also to permit passage of light liquid from the inner regionof chamber 3Id to the inner region of chamber 3 Ic.

The unitv 30h includes an annular plate 46 which is secured to the shaft22 and rotates therewith. A series of blades or ns 41, Figures l and 3,are secured to the plate 4B, these blades being of curved configurationand extending from the center or inner region of plate 46 to theperiphery thereof. A plate 48 is secured to the blades 4l and this platehas a central opening 49 formed therein which' communicates with thelower adjacent impeller chamber Sie. The curvature of the blades 41 issuch that the unit 30h functions as a centrifugal pump impeller and,accordingly, liquidI is conveyed thereby from the inner region of theimpeller chamber 3lev and forced against a double deflector 56 mountedat the periphery of the apparatus.

A pair ofannular members 5Ic, 5Id are closely spaced to unit 36h, and asimilar pair of members Ela, 51h are provided for unit 33a. Member tidis supported by a plate 53 attached to the casing I0 while each of theother members- Ela, 5Ib, 5Ic is supported by the adjacent plate 36; Eachof the members 5I has a flanged portion cooperating with a flange on theadjacent plate 45 or 48 to forma labyrinth seal 54and, in addition, eachmember has a perforated' portion ex-A tending circumferentially of theadjacent impeller 26. Accordingly, it will be apparent thatlight liquiddrawn from the impeller chamber 3Ie by the -unit 30h passes into theinterspace between the members 5Ic, 5Id and casing I0, a portion of thisliquid being directed by deiiector 53 through the member EIC intov theimpeller chamber Sid andthe rest of said liquid' being directedthroughmember 5Icl into the impeller chamber Sie. The unit 30h is also providedwith a series of longitudinally extending sets of bores 56, one set ofthese bores being formed in the' Theouter portion of each of the vanes41. number and size of these bores are determinedby the amount of heavyliquid to be handled by the apparatus. These openings permit-the flow ofheavy liquid from the outer region of the impeller chamber 3Id to theouter region of the impeller chamber 3 I e.

The construction of unit 30a is similar to that ofunit 30h and,accordingly, unit 30a is adapted to convey light liquidv from the innerregion of impeller chamber 3Ic through perforated members 5Ia, 5Ib tothe respective outer regions of chambers 3Ib and 3Ic; Unit 30a alsopermits passage of heavy. liquid from-the outer region of impellerchamber 3Ib to the outer region of impeller chamber 3 I c.

The operation of the contacting apparatus will now be apparent to thoseskilled in the art. As'- surning that the shaft 22 is rotating; it willbe' apparent that `tljie'liquid in each impeller chamber is centrifugedwith the result that the heavier liquid' moves toward .the outerf regionyof thef chamber while the lighter liquid moves toward the inner regionof the chamber. In this man#V ner, a vertical generally cylindricalinterface is formed between the light land heavy liquids in each of theimpeller chambers 3|, the location of the interface being controllableby adjustment of back pressure regulators and |911. Thus, if the backpressure at the' liquid outlet is decreased and the back pressure atheavy liquid outlet |9a is increased, the proportion of heavy liquid inthe vessel is increased, with the result that the vertical cylindricalinterface moves inwardly, that is, its radius is decreased.v'Conversely, if the back pressure at light liquid outlet I1 isincreased and the backfpressure at heavy liquid outlet |905 isdecreased, the proportion of heavy liquid in the vessel is decreased,With'the result that the vertical cylindrical interfacel movesoutwardly, that is, its radius is increased.

The centrifugal separation in the chambers 3| permits countercurrentflow of liquids through the vessel, despite the dispersion of each phaseinto the other in the manner hereinafter described. Thus, assuming thatthe heavy liquid contains a component which is to be extracted by thelight liquid, the heavy liquid entering through inlet |53 and passingdownwardly to outlet |9 is progressively denuded of the component to beextracted therefrom by contact with light liquid which, at the top ofthe vessel, contains a substantial proportion of extracted material butwhich, at the bottom of the vessel, substantially free from extractedmaterial. That is, the light liquid, as it passes upwardly through thevessel from inlet I to outlet I6 becomes progressively richer inextracted material, as it is removed from the heavy liquid. It will benoted that this countercurrent action is made possible by the separationof the phases in each of the chambers 3| for, if this were not donel theliquid in the chamber would be a substantially homogeneous mixture andno countercurrent action could take place. It will be apparent thatcountercurrent flow will also take place if the light liquid contains acomponent to be extracted by the heavy liquid.

In accordance with the invention, this centrifugal separation, whichallows countercurrent operation, is combined with intimate contacting ofthe phases through repeated dispersion of each phase as fine dropletsinto a continuous body of the other phase. It will be noted that in eachchamber 3 la, Sib, 3|c, 32d, the centrifuged liquid moves in a circulardirection, in contact with the inner perforated sleeve 2l and the outerperforated member 5|, a continuous body of light liquid engaging thesurface of sleeve 2l, and a continuous body of heavy liquid engagingthel outer perforated member 5|. Accordingly, heavy liquid collectedfrom the outer regions of the impeller chambers 3m, 3|c by the tubeunits 29a, 29h flows through the sleeves 2l whereby the perforations inthe sleeves divide the stream into droplets which'are subjected to amild shearing action by the light liquid Within the impeller chamber.Similarly, light liquid collected from the inner regions of impellerchambers 26e, 26e by the units 3|la,j30b 'flows through the members 5|and is divided into droplets by the perforations therein, thesedropletsbeing subjected to a shearing engagement by the centrifuged continuousbody of heavy liquid `in the impeller chambers. This shearing actionproduces an extremely intimate engagement between the liquids to becontacted. l j

In impeller chambers "3|b`and 3|d, the entire volume of lightliquidilows`into-`thechamber Y. .although through vperforated memberjand out oikk theV sleeve 21 and out through nipples 56. In impellerlchamber 3|c, a portion ofthe light liquid is recycled, this liquidpassing through opening 49, unit 39a, and perforated member 51h.. Aportion oftheheavy liquid is recycled through the tubes 38`of unit 2gband sleeve 21e. The remainder of the flow in chamber 3|c comprises heavyliquid flowing from nipples 56 in unit 30a to tubes 38 in unit 29h,togethergwith light liquid flowing from openings d3 in unit 29h toopening 49 in unit 30a. Chambers 3|a, 3|e are primarily zones ofunhindered centrifugal separation, although there is someV dispersion ofdroplets of heavy liquid through sleeve 27a into the adjacent continuousbody of light liquid in chamber 3| a. The impellers in chambers 3|a,3|e, together with the screens'ZU, 2| are also useful in purifying theexit streams o1 liquid.

Accordingly, be traced through the entire contacting appara-` tusthrough inlet l5, opening i9 in centrifugal impeller unit Stb, theperforations in sleeve 5| c, the'inner region of impeller chamber Bld,the nipples d3 in' unit 29h, the inner region of im? peller chamber 3|c,the opening 49 in the centrifugal impeller unit 30a, perforated memberSla, the inner region of impeller chamberV 3|b, the nipples d3 in unit29a, land the perforations. in plate 2|, to the light liquid outletl.yIt'will benote'd, however, that a portion of the liquid passing througheach centrifugal limpeller unit 30 is recycled through` the respectiveperforated members 5|b and 5M, the amount of this recycled liquid beingcontrolled by varying the number and size of perforatio'ns. Similiarly,the now ofv heavy liquid may be traced from inlet I8, through the outerregion of impeller chamber 3 la., the tubes 38 in unit 29a, thesleeve2lb, the outer region of impeller chamber 3|b, the openings 56 in unit35M, the outer region of impeller chamber 3|c, the tubes 38 of unit 29h,the sleeve 21d, the outer region of impeller chamber 3| d, the openings5e in impeller unit 3th, and the perforations in plate 20 to the heavyliquid outlet I9. A portion-of the heavy liquid is also recycled throughthe sleeves 2id and 21e, from the units 29a and Zeb, respectively, theamount of this recycled liquid being controlled by the size and spacingof the perforations in said sleeves. i

It willbe apparent that I have provided countercurrent contactingapparatus in which countercurrent iiow is combined with repeateddispersion of droplets of heavy liquid into a continuous phase of lightliquid at the sleeves 2l, and dispersion of droplets of light liquidinto a continuous phase of heavy liquid at perforatedmembers 5|. Thedispersion at members 5| is accompanied by a pronounced shearing actionsince the continuous phase of heavy liquid moves rapidly, in aperpendicular direction, relative to the` radially directed droplets oflight vliquid passing inwardly through the members 5| while the disff,persio'n' at sleeves 2l is accompanied byna milder shearing action. Itis to be clearlyunderstood, however, that very advantageous resultsmaybe obtainecljby the use of ar combination of one method of dispersionwith countercurrent ilow the combination of both methods of dispersionproduces unusually good results.

In some cases, the impellers 2'6 may be replaced by discs which may beVof conical 'configuration eff the dispersal 'sonesthe progress oflight'liquid can though, in 'the described embodiment, 'the .flow ofliquid V'from top to bottom or vice `versa is caused by gravity, this isnot essential,A as my contacting device 'will work equally Well in 'ahorizontal .position provided that the shaft is rotated with sufficient-speed as to provide ya centrifugal force two or three times as large asthe 'force of gravity. If desired, the impellers may be des'ignedtoassist in the movement of light liquid 'from the bottom to the top ofthe vessel and stationary diffuser vanes may be mounted on 'the casingand units 12'9 so as to assist in the movement of heavy liquid throughthe several stages from the top to the bottom of 'the vessel. stagesmaybe varied by providing aV larger or smaller number of impellers 26and units 29 and 30.

While the relative amounts of the two phases within the contactingapparatus is not critical, solong as there is enough of the heavy phasepresent to cover the inlets of elements v29a and 29h, there will be manycases where their rates of feed to the apparatus is quite different. Inmost such cases, as in treatment of a lighter organic phase with aheavier inorganic phase (alkylation, olefin solution in acids) the ow ofthe heavy phase is smaller than that of the light phase. To retainwithin the apparatus 'in such cases a desired ratio of the phases whichis supplied on starting up and which may diner .from the ratio of thefeeds, it is only necessary to adjust the valves l1 and |90, to regulatethe back pressure at the heavy and light liquid outlets. In some cases,the function of the centrifugal impellers 2B may 'be `combin'ed'withthat of the 'centrifugal pump units 39a and '3th 'by providing a pumpunit consisting of `a facing pair of steel stampings keyed to the shaft,upon which are impressed proper 'liquid courses. The space between eachpair of discs forms the unit 30 while .the outer surfaces 'of each suchpair define the centrifugal pump impellers '26. Adjacent each pair ofstampings is a `second vpair of members which are shaped'to form thePitot tube assemblies '29 upon keying of said members to the shaft.

As aspec'ic example of the use of the described contacting apparatus, arelatively heavy liquid such as 'furfu'ral is introduced through inletI8 and passes downwardly through the vessel to heavy liquid outlet IS. Arelatively light liquid,

such `as a hydrocarbon mixture from which irnpurities are to beextracted by the furfural, is admitted through light liquid inlet I5,and this hydrocarbon mixture passes upwardly through vessel lll to lightliquid outlet I6. As the shaft 22 is rotated, droplets of hydrocarbonmixture are dispersed through the perforated members 5l into acontinuous body of furfural, and droplets of furfural are dispersedthrough sleeves 2l into a continuous phase of relatively lighthydrocarbon mixture. vDue to the intimate contact effected by thisdispersion, the impurities inthe hydrocarbon mixture are absorbed by thefurfural. The separation provided by the centrifugal impellers 26 ineachof the chambers 3l permits countercurrent iiow to be obtained. Thus, inchamber 31d, 'the original contaminated hydrocarbon mixture is contactedwith furfural containing a substantial quantity of absorbed impuritiesbut this 'relatively impure furfural is still capable of `absorbing asubstantial quantity of material from the original :hydrocarbon mixture.In `chamber 3Ic, furfural containing a smaller quantity of impuritiesthan that chamber 31d is contacted-with the r`hydrocarbon mixture fromchamber 3 Further, the number of` Id from which, as stated, asubstantial 75 amount of impurities has .already been removed. Inchamber SIb, vhydrocarbon mixture from chamber 3`Ic containing only asmall `amount of impurities .is contacted with the vpure furfuralintroducedthrough inlet .l 8 and-this small or residual amount ofimpurities is readily absorbed by the furfu-ral. It is to be understood,of course, that the `invention is applicable to other types ofliquid-.liquid contacting and the treatment of the mixture of furfuralis set forth as a specific example only.

While the invention has been described in connection with a present,preferred embodiment thereof, it is to be understood that thisdescription yis illustrative only and is not intended to limit theinvention, the scope of Vwhich is defined by the appended claims.

Having described `my invention, I claim:

:1. In apparatus for contacting liquids having different graviti'es, acontacting unit comprising, in combination, a generally cylindricallcas-- ing, a shaft journalled therein, a centrifugal iinpeller mountedon -said shaft, transverse partition plate means extending from thecasing to the shaft at each end of the irnpeller to define with the4casing a chamber 'surrounding the impeller, a ycylindrical metal shellWithin said chamber, said shell being concentric with the casing andclosely spaced to the outer Wall of said casing, said shell having aperforated portion `'disposed circumferentially of said impeller, meansfor estabiishing a flow of relatively light liquid through saidperforated portion into said chamber, perforated sleeve mounted on saidshaft and concentric therewith within said chamber, means forintroducing relatively lheavy liquid into said sleeve and preventingflow thereof through the ends of the sleeve, lwhereby said heavy liquidflows through the perfor-ations in said sleeve into said chamber, meansfor rotating said impeller at such speed as to form a continuous phaseof heavy Vliquid in contact with said perforated portion of the shelland a continuous phase of light liquid in contact with the perforatedportion of said sleeve, and liquid reservoirs at the top and bottom ofthe apparatus.

2. In apparatus for effecting countercurrent contacting of iinmiscibleliquids lhaving different specific gravities, a generally cylindricalcasing, a centrifugal impeller rotatably mounted in said casing, and apair of spaced liquid conveying units each including partition platemeans extending transversely throughout substantially the entire crosssectional area of the casing, said pair of liquid conveying unitscooperating with said casing to denne a chamber housing said impellerand each `unit defining a portion of an adjacent chamber, one of saidunits including means for collecting heavy liquid from the peripheralregion of one adjacent chamber and conveying said liquid to the innerregion of said impellcr chamber, an outlet for light liquid at the innerportion of said one unit, the other unit including means for collectinglight liquid from the inner region of another adjacent chamber andconveying said liquid to the peripheral region of said impellerAchamber, an outlet for heavy liquid at the yperipheral region of saidother unit, and Aliquid reservoirs at the top 4and bottom of theapparatus.

3. In apparatus for eecting countercurrent contacting of immiscibleliquids having different specific gravities, a-caSing, a `shaftvextending -ver- Ltically through .said casing, a centrifugal im-l Vpeller mounted on said shaft, and a pair of vertically spaced liquidconveying units, each extending transversely throughout the regionbetween the casing and shaft, said pair of units including transversepartition plates cooperating with said casing to define a chamberhousing said impeller, and each unit dening a portion of an adjacentchamber, the upper unit including a stationary shrouded impeller forcollecting heavy liquid from the peripheral region of an upper adjacentchamber and conveying said liquid to the inner region of said impellerchamber, an outlet for heavy liquid in the inner portion of saidshrouded impeller, the lower unit including a centrifugal impellerrotatableY with said shaft for collecting light liquid from the innerregion of a lower adjacent chamber and conveying said liquid to theperipheral region of .said impeller chamber, an outlet for heavy liquidin the peripheral portion of said centrifugal irnpeller, and liquidreservoirs at the top and bottom of the apparatus. Y 4. In apparatus foreffecting countercurrent contacting of immiscible liquids havingdifferent specic gravities, a generally cylindrical casing, a shaftextending axially through said casing, an impeller mounted on saidshaft, a cylindrical metal shell within, concentric with and closelyspaced to said casing having a perforated portion disposedcircumferentially of said impeller, a perforated sleeve mountedconcentric and rotatable with said shaft, and a pair of spaced liquidconveying units each including partition plates extending transverselyfrom the shaft to the casing, said units cooperating with said casing todefine a chamber housing said impeller, one of said units including aPtot tube assembly for conveying heavy liquid from the peripheral regionof an adjacent chamber to the interior of said sleeve, means forpreventing ow of liquid out of the ends of the sleeve, said assemblyincluding an outlet for discharging light liquid from the inner regionof said chamber, the other unit including va centrifugal pump assemblyrotatable with said shaft for conveying light liquid from the innerregion of an adjacent chamber to the interspace between said casing andsaid perforated shell, said centrifugal impeller having an outlet formedtherein for discharging heavy liquid from the peripheral region of saidchamber, and liquid reservoirs at the top and bottom of the apparatus.

5. Apparatus for effecting countercurrent contacting of a plurality ofimmiscible liquids of different specific gravities which comprises, incombination, an elongated vessel'having a shaft extending longitudinallytherethrough, a plurality of centrifugal impellers spaced along saidshaft, an inlet for heavy liquid and an outlet and reservoir for lightliquid at one end of the Vessel, an inlet for light liquid and an outletand reservoir for heavy liquid at the other end of said vessel, a liquidconveying unit mounted between each pair of impellers, each unitincluding a partition plate means extending transversely from the shaftto the wall of the vessel thereby defining a series of contactingchambers in said vessel, alternate ones of said units including meansfor transferring liquid in one direction from the inner region of oneadjacent chamber to the outer region of the other adjacent chamber, andthe rest of said units including means for transferring liquid in theopposite direction from the outer region of one adjacent chamber to theinner region of the other adjacent chamber.

10 f Y 6. Apparatus for effecting countercurrentconthrough, a pluralityof impellers spaced along said shaft, an inlet for heavy liquid and anoutlet and reservoir for light liquid at the top of the vessel, an inletfor light liquid and an outlet and reservoir for heavy liquid at thebottom of said vessel, a liquid conveying unit mounted between each pairof impellers including partition plates extending throughout the regionbetween the shaft and walls of the vessel thereby dening a series ofvertically aligned contacting charnbers in said vessel, alternate onesof said units including means for transferring liquid from the innerregion of the lower adjacent chamber to the outer region of the upperadjacent chamber, and the rest of said units including means `jzfortransferring liquid from the outerregion ofthe upper adjacent chamber tothe inner regi the lower adjacent chamber. .l 7. Apparatus for effectingcountercurrentfconltacting of a plurality of immiscible liquidsofdifferent specic gravities which comprisesin cornbiination, an uprightelongated vessel havingya shaft extending longitudinally therethrouglp@plurality of impellers spaced along said shaft, an inlet for heavyliquid and an outlet and reservoir for light liquid at the top of theVessel, an inlet for light liquid and an outlet and reservoirfor heavyliquid at the bottom of said vesse1,- aliquid conveying unit mountedbetween each paingof impellers including partition plate means extendingthroughout the region betweenthe shaftand Walls of the vesselv therebydefining a seriesg'o-f contacting chambers in said vessel, alternateones of said units including a centrifugal pump impeller rotatable withsaid shaft for transferring liquid from the inner region of the loweradjacent chamber to the outer region of the upper adjacent chamber, andthe rest of said units including a series of stationary, generallyradially vextending tubes for transferring liquid from-the outerregionof the upper adjacent chamber to the inner region of the lower adjacentchamber. r

y 8. Apparatus for effecting countercurrentzconitacting of a pluralityof immisciblel liquids .com-,- prising, in combination, an uprightgenerallycylindrical casing, a vertically-extending shaftfjournalled insaid casing, a plurality ofspaced impellers mounted on said shaft,spaced liquid; conveying assemblies mounted vwithin said'casingn;l eachassembly including partition plates extending throughout the regionbetween the shaft and casing, said assemblies defining with the casing aseparate chamber for each impeller, alternate ones of said assembliesincluding means for conveying liquid from the inner region of the loweradjacent chamber, to the outer region of the upper adjacent chamber, andmeans for conveying liquid from the outer region of the upper adjacentchamber to the outer region of the lower adjacent chamber, the otherassemblies including means for conveying liquid from the outer region ofthe upper adjacent chamber to the inner region of the lower adjacentchamber, and means for conveying liquid from the inner region of saidlower adjacent chamber to the outer region of the upper adjacentchamber, said assemblies being constructed and arranged to provide acountercurrent flow of liquids through the apparatus, and unobstructedchambers at the top and bottom of the apparatus.

9. Apparatus for countercurrent contacting of immiscible liquids havingdifferent specific gravitiescomprising, in combination, an elongated cy-,lindrical casing, a shaft journalled therein,

series of Virripellers spaced along and carried by said shaft, firstliquid conveying units mounted between alternate pairs of impellers,second liquid conveying units mounted between the other pairs ofimpellers, said units all extending throughout 4the region between theshaft and casing, and

thereof for passing heavy liquid from the other g Iadjacent chamber tothe rst chamber, and a cylindrical metal shell concentric with andclosely spaced to said casing for receiving light liquid from saidimpeller plate, said shell having perforated portions disposedcircumferentially oi both adjacent impellers for discharging lightliquid into both adjacent impeller chambers, each of said second unitsincluding a perforated sleeve xed to and concentric with said shaf t,said sleeve extending into both adjacent impeller chambers, and a platemeans extending throughout the region between the shaft and casinghaving tubes disposed therein for conveying heavy liquid from the outerregion of one adjacent chamber to the interior of said sleeve, means forpreventing the loW of liquid out of the ends of said sleeve whereby saidheavy liquid flows through the perforations in said sleeve into bothadjacent chambers, said plate means having openings in the inner regionthereof for passing light liquid from one adjacent chamber to the otheradjacent chamber, an inlet for heavy liquid and an outlet and reservoirfor light liquid at one end of said casing, an inlet for light liquidand an outlet and reservoir for heavy liquid at the other end of saidcasing, and means for rotating said shaft to effect countercurrentmovement of said liquids through 'the contacting apparatus.

10. Apparatus for countercurrent contacting of immiscible liquids havingdifferent specific gravities Which comprises, in combination, an uprightelongated casing, a vertically-extending shaft journalled therein, aseries of impellers spaced along said shaft, rst liquid conveying unitsmounted between alternate pairs of impellers, and second liquidconveying units mounted between the other pairs of impellers, said unitsextending from the shaft to the casing to form a series yof verticallyspaced impeller chambers, each of said rst units including a centrifugalimpeller fixed to said shaft for conveying light liquid from the innerregion of the lower adjacent chamber to the periphery of said casing,said rst units having vertically-extending openings formed in theperipheral portions thereof for passing heavy liquid from the upperadjacent chamber to the lower adjacent chamber, and a cylindrical metalshell concentric with and closely spaced to said casing for receivinglight liquid from said impeller plate, said shell having perforatedportions disposed circumferentially of both adjacent impellers tordischarging light liquid into both adjacent impeller chambers, each ofsaid second units including a perforated sleeve fixed to and concentricwith said shaft and extending into both adjacent chambers, means forpreventing flow of liquid from the ends of said sleeve, and tubes forconveying heavy liquid from the outer region of the upper adjacentchamber to the interior of said sleeve whereby said heavy liquid owsthrough the perforations in said sleeve into both adjacent chambers,said second units having openings in theinner portion thereof forpassing light liquid from *the lower adjacent chamber to the upperadjacent chamber, an inlet for heavy liquid and an outlet and reservoirfor light liquid at the top of said casing, an inlet for light liquidand an outlet and reservoir for heavy liquid at the bottom of saidcasing, and means for rotating said shaft to effect countercurrentmovement of said liquids through the contacting apparatus.

SAMUEL C. CARNEY.

Number Name Date 1,231,410 `Moore June 26, 1917 1,845,128 Coahson Feb.16, 1932 2,000,606 Othmer May 7, 1935 2,036,924 Coutor Apr. 7, 19362,063,789 Burk Dec, 8, 1236 2,072,382 Robinson Mar. 2, 1937 2,154,150Becze Apr. l1, 1939 2,266,521 Van Dijck Dec. 16, 1941 2,493,265 ScheibelJan. 3, 1950 FOREIGN PATENTS Number Country Date 489,632 Germany Mar.11, 1922 566,945 Germany Dec. 28, 1932 585.517 Germany Oct. 10, 1933

1. IN APPARATUS FOR CONTACTING LIQUIDS HAVING DIFFERENT GRAVITIES, ACONTACTING UNIT COMPRISING, IN COMBINATION, A GENERALLY CYLINDRICALCASING, A SHAFT JOURNALLED THEREIN, A CENTRIFUGAL IMPELLER MOUNTED ONSAID SHAFT, TRANSVERSE PARTITION PLATE MEANS EXTENDING FROM THE CASINGTO THE SHAFT AT EACH END OF THE IMPELLER TO DEFINE WITH THE CASING ACHAMBER SURROUNDING THE IMPELLER, A CYLINDRICAL METAL SHELL WITHIN SAIDCHAMBER, SAID SHELL BEING CONCENTRIC WITH THE CASING AND CLOSELY SPACEDTO THE OUTER WALL OF SAID CASING, SAID SHELL HAVING A PERFORATED PORTIONDISPOSED CIRCUMFERENTIALLY OF SAID IMPELLER, MEANS FOR ESTABLISHING AFLOW OF RELATIVELY LIGHT LIQUID THROUGH SAID PERFORATED PORTION INTOSAID CHAMBER, A PERFORATED SLEEVE MOUNTED ON SAID SHAFT AND CONCENTRICTHEREWITH WITHIN SAID CHAMBER, MEANS FOR INTRODUCING RELATIVELY HEAVYLIQUID INTO SAID SLEEVE AND PREVENTING FLOW THEREOF THROUGH THE ENDS OFTHE SLEEVE, WHEREBY SAID HEAVY LIQUID FLOWS THROUGH THE PERFORATIONS INSAID SLEEVE INTO SAID CHAMBER, MEANS FOR ROTATING SAID IMPELLER AT SUCHSPEED AS TO FORM A CONTINUOUS PHASE OF HEAVY LIQUID IN CONTACT WITH SAIDPERFORATED PORTION OF THE SHELL AND A CONTINUOUS PHASE OF LIGHT LIQUIDIN CONTACT WITH THE PERFORATED PORTION OF SAID SLEEVE, AND LIQUIDRESERVOIRS AT THE TOP AND BOTTOM OF THE APPARATUS.